Method of selective oxidation and apparatus therefor



Mar, 13, 1923.

. W. A. DAR

RAH

' METHOD OF SELECTIVE OXIDATION AND APPARATUS THEREFOR Filed Dec. 11, 1919 4 J IIIIIIIHIH Llll INVHNTOR.

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Patented'Mar. 13, 1923.

UNITED STATES PATENT OFFICE.

WILLIAM Aosrm DABRAH, or CHICAGO, ILLINOIS.

METHOD .OF SELECTIVE OXIDATION AND APPARATUS THEREFOR.

Application filed December 11, 1919. Serial 1%. 344,224.

reference being had to the accompanying drawings, forming a part of this specification. I This invention relates to methods of partially oxidizing various compounds with a view of producing new materials from various raw materials. This invention is particularly adapted for treating oils, paraffins, methane and similar substances, although .it should not be limited to these particular materials.

In the case of fuel oil this invention is particularly adapted to the production of a high grade of lamp black by consuming only a portion of the carbon contents of the oil.

The method here described offers numerous advantages, as will appear in the subsequent description. In producing lamp black from fuel oil or tar residues, it makes possible the eilicient transformation of a low grade material into a high quality of lamp black. By this method the losses by oxidation are much smaller than by other methods and practically no labor is required,

the process being substantially automatic.

specifications. r

The description of this method Will be confined specifically for purposes of illustration, to the production of lamp black, but

it should be understood that this invention is not limited to this field alone, as it is possible to make such products as aldehydes, acetones. alcohols, and other partial oxidation. products, without exceeding the scope of this invention, and with relatively little modification in the apparatus.

It isa well known fact thatl'to produce a grade of lamp black or carbon blackwhich will command a high price in the trade, .it

is necessary that it conform to certain rigid I specifications. It is usually required that Other advantages of 40 this process will appear in the following the ash content, shall be less than 1%, while certain consumers insist on an ash content of less than 0.1%. vA good lamp black must be relatively free from oils, tars, or'

similar materials, which are removed by solution with acetone. .The subdivision must be very great. In order to make a productsuitable for the ink and rubber trade, it has so far been found necessary to limit consumption to lamp blacks, the ultimate particles of which have a diameter less than one micron. It has also been found necessary to restrict consumption in the rubber and ink trade to a lam black hav-. ing the maximum' number of 'ne particles and the minimum number of aggregations of particles. In the case of good grades of carbon black the size of the aggregations averages about 100 microns.-

From the above brief description it will be evident that the production of a high grade of lamp black is a matter requiring careful attention, and not an easy and to obtain without the proper apparatus. In addition to the above noted physical characteristics, the color of theblack is of considerable importance, many lamp blacks suffering a material reduction in selling price because of the brownish tinge which they display on careful examination.

It has been found impossible to produce a high grade of lamp black or carbonblack by grinding any known form of solid carbon. A consideration of the extreme fineness of .particles will make the basis of this limitation evident. It has in allcases been found necessary to produce lamp black or carbon black by precipitation of the solid carbon from gases. Precipitation has been accomplished satisfactorily in commercial quantities both by allowing the carbon containing gases to come into contact with a relatively cool solid body, or by cooling the gases by expansion, or other means.

In the case of fuel oil, approximate analysis indicates that it contains about 84% carbon, l'5%-hydrogen, and a balance of 1% distributed among such gases as oxygen,

nitrogen, etc. In the case of natural gas the carbon content is around 70%, the balance being hydrogen, nitrogen and oxygen.

I have found that by. mixing the vapor of fuel oilfor natural gas with an' excessv of the products of combustion of the fuel oil orv natural gas, and with an amount of air only suflicient to consume the hydrogen content of the oil or gas, it is possible to produce a high grade ofblack with an efliciency of recovery hitherto impossible.

It appears from my investigations thatluting gas is whol y nitrogen. A practical means of securing a commercially satisfactory diluting gas, consists in drawing prod uctsfrom the flues, as shown in the drawing, and mixing said combustion products with the incoming air. Another means of acof oxygen be limited to that present.

complishing the same result would be to pass the incoming air over a glowing bed of'coal, charcoal, coke, etc.', producing the equivalent of producer gas.

It is not essential that the exact amount quantity theoretically ile probably this would be the theoretical amount, I have found that 50% to 75% more oxygen produces a higher grade of black, although it results in a somewhat lower carbon recovery.

For practical conditions, I have found that the total amount of gas necessary should be approximately equal to'the total amount of air which would ordjnarily'be required to give complete combustion to the oil or gas used. In other words, approximately 1500 cu. ft. of gas (total inert gases and air) is a commercially satisfactory quantity for the-consumption of-one gallon of fuel oil. It should be understood that I do not wish to be restricted to this figure, as I have foilnd wide variations possible without seriousl influencing the quality of the prodpct. 'fhe particular design of apparatus un doubtedly has a very important bearing-on the quantity of gases employed in the partial-oxidation process. Too little diluting gases results in a black containing quantities of oily matter,

having a brownish shade. In the case of natural gas an equivalent amount of total gases (8000 cu. ft. per 1000 cu. ft. of naturalI gas) gives satisfactory results.

ave found that best results are secured when the above mentioned 1500 cu." ft.- of gases are divided-in the ratio of about one. part air and two parts flue gases. This ratio is also subject to considerable variation without seriously affecting the proreayq lllired to consume the hydrogenonly, many large some grit, andamount of gas delivered to bu it is possible to secure satisfactory results with somewhat lower gastemperatures in case natural gas is employed.

In case itis desired to precipitate the carbon upon a cold surface, as shown in the attached drawing, the best-results are usually obtained when the temperature of the surface is approximately 300 F.

'It will be evident that the-temperature of the precipitating surface can readily be controlled in the case of the apparatus shown in the attached drawing, by regulating the amount of fuel which isconsumed in a given period. Sincethe radiation from the precipitating surface is approximately a con-- stant quantity, the consumption of fuel will control its temperature.

Referring to the drawing, Figure 1 indicates a sectional elevation through one form of apparatus designed to carry out the process of this invention. It should be understood that Figure 1 is purely schematic, be.- ing intended for purposes of illustration obvious modifications being re-,

quired to conform t6 local practical conditionsr In the drawing (1) refers to a rotating cylinder or drum mounted upon supports (2) and (3) in such manner that it can revolve upon rollers (4) and (5). Rotation may be produced by any convenient mechanical driving means.

A venturi shaped burner (6) is mounted upon a stationary support (7) which also carries, blower (8).- A pipe 9) serves to bring natural gas' or fuel oil (or other fuel) to burner (6).

Burner (6) is provided with a narrow throat (10) surrounded by a channel of torous form through whichthe fuel is introduced into the burner (6), port (11).

Burner (6 pipe (12). e blower is connected to the. flue passage (13) by pipe (14) in which is inserted butterfly valve (15). Pipe (16) connects blower (8 with air heater (17) which secures outsl e air through inlet (18) Butterfly valve (19) regulates the flow of air thru pipe (16).

A butterfly valve (20) is inserted between blower (8) and the uni n (14) and (16) in order th by way of the) total r 6 may be under control. p rill Rotating cylinder (1 which may well'be is connected to blower (8) by i of pipes made of metal, is provided internally with an arm (21) supported by bracket (22) mounted upon upright channel A series of carbon removing devices (24:) is' fastened to bracket (21) and serves to remove the deposit of carbon as the drum rotates. The said carbon removing devices may be in the form of wire brushes, chains, or other equivalent means. I may even fasten a series of chains longitudinally to the inner surface of rotating cylinder (1) and by providing sufiicient looseness in said chains, cause them to brush the carbon deposit from the walls of the drum as the device is rotated. Many other equivalent means will be apparent.

Drum (1) is shown slightly inclined in order that as the carbon is brushed from the surface by rotation it will slide down toward the lower end of the drum and be directed by inclined surface (25) to conveyor (26) which serves to carry it to the storage bin or any other desired point.

The warm gases leaving drum (1) usually carry appreciable amounts of carbon in suspension. These gases on entering chamber (27) are materially decreased in speed, with the result that a portion of the carbon falls to the bottom of'chamber (27) and passes on to conveyor.

The waste gases pass from chamber (27) around deflector (28) to chamber (29).and'

thence to flue (13). It has been my experience that some .portions of carbon will deposit on the walls of chamber (29) and flue (13) so that provision has been made by outlet (30) to allow thismaterial to pass to conveyor (26).

Flue gases then continue through port into the base of chimney (32) from which they circulate over air heaters (17) and finally pass up stack (33). An auxiliary burner (34:) is provided in the base of stack.(32) in order to insure that the temperature of the incoming air in heaters (17) shall be sufliciently high.

The operation of this device will be evident from the construction described above.

and the description given in this specificatlon. Operation may be briefly out-lined as follows:

The mixture of heated flue gases and air is forced by blower (8) through venturi throat (10). The rapid increase in velocity caused by the contraction of the throat creates a materially reduced pressure at that point. The entering oil or gas to becarbonized, is preheated by circulating,

and insufiicient air for complete combustion,

are very thoroughly mixed and superheated.

Under these conditions the mixture will immediately undergo carbonization as soon as the speedis reduced. The result is a yellow, carbon-depositing flame in' drum (1). This flame on comin into contact with therelatively cool meta surface, deposits the greater portion of its carbon at this place, and by maintaining the temperature of this surface at the proper value, the carbon thus formed is of a dense black variety, quite free from materials soluble in acetone and free from grit. v

By using this process it is possible in the case of natural gas to obtain a far higherrecovery than by any of the commercial methods now employed. When properly controlled, the quality of the material is equal to the best carbon black.

It will be obvious that many of the mechanical arrangements here described may be substituted by other mechanical devices without departing from the method which forms the basis of this invention. The devices shown, however, represent one arrangement which has proven satisfactory in practice.

In order to clearly set forth the basis of this invention, it: should be pointed out that the function of the diluting or inert gases is at least two-fold. In other words, by pro-, viding a large body! of gases whose temperature must be raised before the temperature of the flame can reach high values, I' am providing a means of controlling the maximum flame temperature. It is a well known fact that high temperatures have a decided tendency to cause grit or adamantine carbon which is very undesirable in either lamp black or carbon black. The presence of the diluting gases make the formation of this undesirable product impossible. The diluting gases also serve to prevent the oxidation of-the carbon when the said diluting gases contain large quantities of the oxides. of carbon. The effect in this case will be evident from a consideration of the fundamental principles of the mass action law, on the principle that the accumulation of the products of any reversible reaction tends to revent the progress of the said reaction. presence, therefore, of the oxides of carbon tends to reduce the-oxidation of the carbon The diluting gasesalso materially assist in the thorough vaporization of the hydrocarbon and reduce the possibility-of. any

subsequent condensation of the hydrocarbon.

The effect of. this action is to cause the resultant carbon deposit to be relatively free from oils or other soluble materials.

One advantage of the diluting gases re- It will be understood that any or all of the" above re-actions may take place with the formation of carbon monoxide and hydrogen, as outlined above, andthat under such conditions the valuable. products of the reaction would be the gases which would be collected from stack (33) in any suitable manner. Obviously, these gases may be used for fuel purposes, if so desired.

'While the abovedescription has been con fined largely to the specific term oxidation it should be kept in mind that the term oxidation or combination is not restricted to the addition of oxy n to various compounds but may be app ied with equal correctnes's to the addition of chlorine, sulphur, sulphuric acid, nitric acid, or any other radicles. fore, should not be restricted to oxygen compoundstalone.

It will be understood that the combination of chlorine, sulphur radicals, or similar sub-- stances may be substituted in place of oxygen and similar equipment may be used.

avi ng now fully described my invention, what I claim'as new and wish to secure by Letters Patent is as follows I claim: Y

1. The method of partially oxidizing substances, which consists in vaporizing the substance to be oxidized, mixing the vapor thusproduced with preheated diluting gases and. msufliclent air for complete burning said mixture combustion, and collecting the products of the reaction.

2. The methodof partiallyoxi-dizing substances which consists in mixing the subsubstances by mixing the said substance in gaseous 'form with a small amount of oxygen and ;a quantity pf the oxidized product of; the constituent of said compound The basis ofthis invention there-' 4. The method of oxidizing hydrocarbons which consists in mixing said hydrocarbon in gaseous form with a heated mixture of an oxide of carbon and insufiicient oxygen for complete combustion, and controlling the temperature of the reaction by the quantity and temperature of the added gases.

5. The method of separating carbon from hydrocarbons by mixing the said hydrocarbon in gaseous form with heated diluting gases and insufiicient heated oxygen for complete combustion of the hydrocarbon and finally collecting the solid carbon formed by the reaction upon surfaces which are cooler than the flame.

6. Themethod of separating carbon from hydrocarbons by mixing said hydrocarbon in gaseous form with heated products of combustion and insuflicient heated air for complete combustion, causing said combustion to take place in a closed okigiber and collecting the products of the ction, on a cooling surface.

7. The method of producing lampblack which consists in adding to a hydrocarbon in gaseous form insuflicient heated air for complete combustion said heated air being previously mixed with heated flue gases, and collecting the resulting carbon on a cooling surface.

8. The method of producing lampblack which consists in heating a hydrocarbon, adding said heated hydrocarbon to a stream of heated flue gases and air under reduced pressure, and collecting the resulting carbon.

9. As a product of manufacture, a form of carbon precipitated from a hydrocarbon by heating to a controlled temperature a mixture of said hydrocarbon, heated flue gases, and insufiicient oxygen for complete combustion.

10. The method of oxidizing a hydrocarbon which consists in mixing said hydrocarbon in gaseous form with insuflicient oxygen for complete combustion and controlling the temperature of the reaction.

11. The method of oxidizing a hydrocarbon in gaseous form with insufficient oxygen for complete combustion, and controlling the temperature of the reaction by adding a given amount of diluting gases at a controlled temperature.

12. The method of' oxidizing a hydrocarbon in gaseous form with insufficient oxygen for complete combustion, and controlling the temperature of the reaction by adding a controlled amount of diluting gases at a controlled temperature, said diluting gases containing some of the products of said oxidation.

13. An apparatus for producing lamp black, consisting of a gas mixing device, a combustion chamber in which hydrocarbons may be added to gas mixed in said gas mixing device, an enclosed surface for collecting the resultant carbon, and a duct for removin -the products of combustion.

14. apparatus for producing carbon, consisting of a gas mixing device, a combustion chamber in which hydrocarbons may be added to gas mixed in said gas mixing device, an enclosed surface for collecting the resultant carbon, means for removing said carbon from the device, and a duct for removing the products of combustion.

.15. The method of partially oxidizing hydrocarbons, which consists in introducing the substance to be partially oxidized, into a rapidly movingcurrent of preheated gases containing insuflicient oxygen for complete combustion, the pressure of the gases being lower at the point of introduction of the hydrocarbon than at any other point in the system. a

16. The process of partially oxidizing the hydrocarbon to be partially oxidized, into a moving stream of heated products of combustion and air under reduced pressure.

17. The process of partially oxidizing hydrocarbons, which consists in introducing the material to be partially oxidized, into a moving stream of heated products ,of combustion and air, said heated products being expanded to occupy a materially reater volume than under atmospheric conditions of pressure and temperature.

18. The process of partially oxidizing hydrocarbons, which consists in introducing the hydrocarbon to be partially oxidized, into a moving stream of expanded products of combustion and air.

In witness whereof, I hereunto subscribe my name this fourth day of December, A. D. 1919. 1

WILLIAM AUSTIN DARRAH.

hydrocarbons, which consists in introducing I 

